This invention relates to electrical control systems, in particular systems for controlling generating sets, and most particularly hydroelectric generating systems.
A generating set includes a prime mover and an electrical generator, and may supply a load within its own system or may supply a grid. The prime mover might be a water-driven turbine, or a diesel engine, for example. The output power to the load from the generating set is not readily controlled by mechanical means, and not rapidly. Electrical control tends to involve dissipation of energy in a non-useful way.
Proposals have been made to provide control of a generator by keeping the load constant. In British patent specification No. 2006998A, for example, a ballast load is shunted across the actual load, and is controlled in dependence upon the generator output voltage or frequency. Nevertheless, such systems are incomplete, in that although the load supplied may be kept substantially constant, nothing is done to alter the running of the prime mover, so that the generator output is matched to the new actual load.